SPC Apr 20, 2025 Day 4-8 Severe Weather Outlook

Day 4-8 Outlook

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0323 AM CDT Sun Apr 20 2025

Valid 231200Z - 281200Z

...DISCUSSION...
A low-amplitude southwesterly flow regime will prevail for much of
the Day 4-8 period across portions of the central and eastern U.S.,
with a mean upper trough persisting across the western states.
Persistent south/southeasterly low-level flow across the Gulf and
southern Plains will result in northward transport of rich
boundary-layer moisture across the southern and parts of the central
Plains through at least Day 6/Fri. Forecast guidance suggests weak
shortwave impulses may float through modest southwesterly flow Days
4-5/Wed-Thu, perhaps providing some support for isolated to
scattered thunderstorm potential across the warm sector over
TX/OK/KS. Given a moist and unstable airmass, at least some severe
potential will exist. However, where exactly severe potential may
develop Day 4-5/Wed-Thu is uncertain given a lack of stronger
large-scale ascent and absence of any substantial surface
cyclogenesis, coupled with modest deep-layer flow. This precludes 15
percent probabilities at this time, though outlook areas could
become necessary in later outlooks as smaller-scale features become
better resolved.

A period of weak upper ridging may spread across the Plains and the
eastern U.S. on Days 6-7/Fri-Sat ahead of a more substantial upper
trough developing over the western U.S. This may limit severe
potential late in the week before the western upper trough ejects
east toward the end of the forecast period.

Read more